Cephalosporins having a ureido acyl side chain are disclosed in U.S. Pat. Nos. 3,673,183; 3,833,568; and 3,708,479. Cephalosporins having an (oxopyridazinyl)thiomethyl group in the 3-position are disclosed in British Pat. No. 1,363,33. Cephalosporins having a methoxy group in the 7.alpha.-position are disclosed in various U.S. patents including U.S. Pat. Nos. 3,775,410; 3,780,031; 3,780,033; 3,780,034; 3,780,073, etc.